Hypertensive disorders of pregnancy — structured SAQ (15 marks)

(a) Classification and why the label is provisional (3 marks)

One mark for correct application of ISSHP 2021, one for naming the specific ambiguity, one for stating how it is resolved. ^[1]

• Apply ISSHP 2021 by timing first. Hypertension known before pregnancy or present before 20 weeks is chronic hypertension, white coat hypertension or masked hypertension. Hypertension arising at or after 20 weeks is transient gestational hypertension, gestational hypertension or preeclampsia.^[1]
• She cannot be classified today because she has no reading before 20 weeks. She may have chronic hypertension only now detected, or genuinely new hypertension after 20 weeks.^[1][6]
• State the mechanism of the trap: the physiological mid-second-trimester blood pressure nadir means even a documented normal reading at 18 to 20 weeks would not exclude chronic hypertension.^[1][6]
• Resolution: the definitive label follows her postnatally — persistence of hypertension beyond 12 weeks postpartum reclassifies her as chronic hypertension. Manage her in the interim as if preeclampsia is possible.^[1][2]

(b) Investigations today (4 marks)

Half a mark per correctly paired test and consequence, maximum four. ^[1][2]

Marks are lost for "routine bloods" without naming the thresholds, and for omitting the fetal assessment. ^[1]

(c) Pharmacological management and target (4 marks)

One mark for the correct agent with dose, one for titration, one for the target, one for the trial evidence. ^[2][4]

• First line: labetalol per the current protocol starting dose and titration. Absolutely contraindicated in asthma.^[2][3]
• Alternatives: nifedipine modified release or methyldopa per the current protocol doses, stopped postnatally in the case of methyldopa because of depression risk.^[2][6]
• Target: below 140/90 mmHg.^[4]
• Evidence: CHAP randomised 2,408 women with mild chronic hypertension and showed that treating to below 140/90 mmHg reduced the composite of severe preeclampsia, indicated preterm birth before 35 weeks, abruption, or fetal or neonatal death from 37.0% to 30.2% (adjusted risk ratio 0.82) with no increase in small-for-gestational-age birth weight (11.2% versus 10.4%). CHIPS had earlier shown tight control was safe, with severe hypertension in 27.5% versus 40.6% with less-tight control.^[4][5]
• Also state: aspirin should already be running for preeclampsia prophylaxis, and never prescribe an ACE inhibitor, angiotensin receptor blocker or atenolol.^[6][2]

(d) The severe-range emergency at 31 weeks (4 marks)

One mark each for: urgency and time target with a named agent and dose; magnesium; investigations and fetal assessment; escalation, fluid and disposition. ^[3][7]

• Treat within 30 to 60 minutes of the confirmed severe reading. Choose from labetalol, hydralazine, or immediate-release nifedipine per the current protocol doses. Target after treatment per the current protocol range, avoiding a precipitous fall.^[3]
• Magnesium sulfate per the current protocol loading and maintenance doses for seizure prophylaxis — she has severe-range hypertension plus a neurological symptom. Magpie showed magnesium cut eclampsia by 58% (0.8% versus 1.9%).^[7][2]
• Investigate and assess the fetus: full blood count, creatinine and electrolytes, liver enzymes, urate, protein:creatinine ratio, group and hold, coagulation if platelets are low; cardiotocography and ultrasound for growth, liquor and Doppler.^[1][3]
• Escalate and support: admit, senior obstetrician and anaesthetist, restrict fluid per the current protocol rate, give betamethasone per the current protocol dosing for fetal lung maturity, involve neonatology, and plan the timing of birth.^[3][1]